Corma Inc. of Toronto, Ontario, Canada has for many years been manufacturing and selling plastic pipe molding equipment. This equipment includes mold block sections circulating on endless tracks and meeting with one another to form complete mold blocks which are carried along a moving mold tunnel. The Corma mold blocks feature slit-like openings on the interior surfaces of the mold blocks which provide openings for drawing air out of the mold blocks. These vacuum slit bearing mold blocks have proved extremely efficient in the vacuum forming of plastic pipe where the vacuum has been induced from both mold block sections. They have also, to a lesser extent, been used in the blow molding of pipe.
To date, the Corma mold block has not been used for cooling purposes where it is very important to provide cooling of both the pipe and the mold blocks used in making the pipe. Such cooling substantially increases production speeds of the pipe mold.